To limit the resources used by an active map reassignment job, reduce the number of sessions processing the map use changes. In the following example, the time is 8 AM, the system is busy, and the DBA stops 5 of the 8 Mover sessions that started at 6 PM last night:
CALL TDMaps.StopMoverSP(5);
StopMoverSP does not end any ALTER TABLE requests in progress.